Two　CeO2　catalysts　were　fabricated　by　dry　ball　milling　in　the　absence　or　presence　of　organic　ligand,　denoted　as　CeO2-A　and　CeO2-B,　respectively,　and　tested　for　selective　catalytic　reduction　of　NO　by　NH3　(NH3-SCR).　It　was　found　that　the　CeO2-B　catalyst　exhibited　high　NH3-SCR　activities　as　well　as　high　SO2　and　H2O　resistance.　The　characterizations　of　nitrogen　adsorption　(BET),　X-ray　diffraction　(XRD),　Fourier　transform　infrared　spectroscopy　(FTIR),　thermogravimetric　analysis　(TG),　Raman　spectroscopy,　temperature-programmed　reduction　(H-2-TPR),　temperature-programmed　desorption　(SO2-TPD)　and　X-ray　photoelectron　spectroscopy　(XPS)　revealed　that　the　addition　of　adipic　acid　in　the　synthetic　procedure　leaded　to　a　high　reducibility　of　cerium　species　and　a　special　surface　microstructure,　including　relative　high　surface　defects　and　hierarchical　pore　structure　of　the　CeO2　catalyst,　which　played　important　roles　in　enhancing　NH3-SCR　performance.　Meanwhile,　the　interaction　between　SO2　and　CeO2　under　different　condition　was　investigated　in　detail　by　insitu　diffuse　reflection　infrared　Fourier　transform　spectroscopy　(DRIFTS)　and　SO2-TPD.　The　data　suggested　that　the　high　resistance　to　SO2　poisoning　of　CeO2-B　could　be　explained　by　a　low　amount　of　sulfur　species　formation　and　a　low　speed　transformation　of　sulfites　to　sulfates　on　the　ceria　catalyst　due　to　its　special　surface　microstructure.